In heavy duty trucks and other large industrial and commercial motor vehicles, it is desirable to provide a readily accessible external source of 12 volt direct current voltage, both positive and, in some cases, negative terminals for providing jump start capability for powering emergency light sources, running electric air compressors and the like.
On large commercial and industrial vehicles, it is common to have a metal battery box that completely encloses the single or multiple storage battery electrical source. Typically, this battery box may be located outside of the engine compartment or cab of an over-the-road truck in proximity to the running board or gasoline tanks. Since the batteries are positioned outside of the vehicle, the battery boxes have tightly closed covers that protect the batteries from the elements. Jump start connectors may extend through the battery box sidewall. Typically, these connectors may extend through apertures in the side wall of the battery box and include some type of insulative cap or cover which can be removed to provide access to the positive hot terminal and/or the negative ground terminal. Prior stud-type through the wall connectors have included connectors composed, in the main, of threaded stud bolts having insulative jackets positioned thereover including a pair of opposing frame mounting bolts, one on each side of the current carrying studbolt.
One other prior type of stud connector includes an annular insulative jacket positioned over a central portion of the stud bolt and held in position by a metal washer soldered at its interior aperture to the stud bolts. Problems with this type of through-the-wall connector occur when cable connectors are mounted on the threaded end of the stud bolt such that a major portion of the current passing therethrough passes from the stud bolt through the washer and onto the metal end of the cable connector. The soldered joint between the stud bolt and the washer becomes critical to the transmission of current from the stud bolt to the cable connector and it is the weakest conductive link in the stud connector. Additionally, the washer holding the annular insulator in place gives the appearance that the body of the stud connector is much more metal massive than is the case in reality, with a viewer imagining that the metal of the washer extends axially through the connector.
A need has developed for a through-the-wall connector wherein the current carrying portion of the connector is made of a single piece of metal and is more substantial than heretofore known. A need has also developed to be able to position additional through-the-wall electrical connectors of differing physical sizes at remote positions away from the battery box of a vehicle for more convenient access to a 12 volt direct current source.
A need has also developed to provide a through-the-wall connector with annular insulator portions surrounding the central body of the stud connector and mounting same on the wall also enabling the connector to be mounted to walls of differing thicknesses.
It is therefore an object of the present invention, generally stated, to provide an improved through-the-wall stud type connector with improved current carrying capacity and mounting adjustability to fit through differing sized wall panels.